4.13 B) Iii) Metabolic Hyponatraemia

Front 1

Which is not a criteria for Dx of SIADH?

1. urine sodium > 20 mmol/L
2. hypotonic hyponatraemia
3. normal cardiac and renal function
4. presence of hypovolaemia/ hypotension
5. normal adrenal and thyroid function

Back 1

4. ABSENCE of hypotension, hypovolaemia

= Euvolaemic Hypotonic

Front 2

Causes of hypervolaemic hyponatraemia {3} ?

Back 2

1. CCF
2. Renal Failure
3. Hepatic cirrhosis

Front 3

Causes of Euvolaemic hyponatraemia {2} ?

Back 3

1. SIADH [ High urinary sodium]
2. Water intoxication [ normal urinary sodium]

Front 4

Causes of Hypovolaemic hyponatraemia

Back 4

1. Adrenocortical insufficiency

[ High urine sodium / low aldosterone]

2. Diuretics

[ High urine sodium / normal aldosterone]

3. GIT Losses
a. Upper GIT losses [ Alkalosis]
b. Lower GIT losses [ Acidosis]

Front 5

Causes of Hyponatraemia with

High Urine sodium ?

Back 5

1. SIADH
2. Diuretics
3. Adrenocorticoid deficiency
4. Nephropathy

Front 6

Causes of Hyponatraemia with Low / normal urine sodium?

Back 6

1. CCF
2. Hepatic cirrhosis
3. Renal Failure
4. GIT losses

Front 7

Which is incorrect regarding hyponatraemia?
A. It is the most common electrolyte disorder
B. Most cases of hyponatraemia are caused by drugs.
C. It is defined as a serum sodium < 135 mmol/L
D. Severe hyponatraemia is defined as a sodium < 120 mmol/L, and

is a Medical Emergency.

Back 7

B. Not strictly correct.

There are 3 main causes:

1. Drugs
2. SIADH
3. Fluid retaining conditions - eg. CCF

Front 8

Which is not a well recognised association of

hyponatraemia ?
A. Increased morbidity and mortality in

Hospitalised patents.
B. Prolonged Hospitalisation
C. Increased mortality in patients with

Community acquired pneumonia (CAP).
D. Cushing's Disease

Back 8

D. Addison's Disease, or adrenocortical

insufficiency.

Front 9

True or False: By far the commonest cause of hyponatraemia in Clinical Practice is "dilutional hyponatraemia" due to the retention of water in excess of sodium ===> SIADH

Back 9

True

Front 10

In regards to Euvolaemic Hyponatraemia, which is incorrect?
A. It is the most common form of hyponatraemia
B. SIADH has a higher urine osmolality than

plasma osmolality.
C. Pneumonia causes SIADH
D. Exercise -associated hyponatraemia is a

hypovolaemic condition-not euvolaemic.

Back 10

D. Exercise -associated hyponatraemia is

Euvolaemic- due to excessive hypotonic fluid

intake during extreme exercise.

Front 11

List the 4 broad categories of the causes of SIADH.

Back 11

1. Head -CNS
2. Chest- Respiratory
3. Occult Malignancy
4. Miscellaneous

Front 12

What are the CNS causes / associations of SIADH?

Back 12

1. Stroke / CVA / ICB
2. CNS infection ( meningo-encephalitis )
3. Hydrocephalus
4. Cerebral tumour
5. Neurosurgical procedures - pituitary

Front 13

What are the Respiratory causes / associations with SIADH?

Back 13

1. Pneumonia
2. Asthma
3. Pneumothorax
4. Respiratory Failure +/- PPV
5. Pulmonary malignancies :

mesothelioma / SCC lung
6. Major thoracic surgery

Front 14

What are the Malignancies associated / causative of SIADH?

Back 14

1. Pulmonary ( mesothelioma / SCC lung )
2. Head and neck malignancies
3. Lymphoma

Front 15

List the miscellaneous conditions associated / causative of SIADH.

Back 15

1. Hereditary
2. HIV / AIDS
3. Guillain Barre Syndrome (GBS)
4. Multiple sclerosis (MS)

Front 16

Which is not a cause / association of

hypovolaemic hyponatraemia.

A. Thiazide diuretics
B. Cerebral salt wasting
C. Liver failure
D. Nephropathy

Back 16

C. = Hypervolaemic

A: Thiazides can cause hypovolaemic or

euvolaemic-the latter being more common
B: Occasional cause in Neurosurgical patients / patients with SAH

Front 17

List the main drugs associated with

hyponatraemia.

Back 17

1. Diuretics
2. Antiepileptics ( carbamazepines ; valproate )
3. Antidepressants ( SSRI ; TCA ; Venlafaxine )
4. Antipsychotics

( phenothiazines ; haloperidol )
5. Recreational drugs ( MDMA - ecstasy )
6. NSAIDS

Front 18

What type of hyponatraemia would be

expected with a low plasma sodium and

impaired renal function: hypervolaemia,

euvolaemic or hypovolaemic ?

Back 18

Hypervolaemic hyponatraemia.

Front 19

What types(s) of hyponatraemia would be

expected with a low plasma sodium and

normal renal function

( normal creatinine and urea)?

Back 19

Likely a "dilutional hyponatraemia" :

1. Euvolaemic
2. Hypervolaemic

Front 20

A maximally dilute urine has an osmalality of how many mmol/L

Back 20

< 100 mmol/L

Front 21

A urine osmolality of > 200 mmol/L indicates what 2 potential abnormal processes in

euvolaemic hyponatraemia?

Back 21

1. Lack of appropriate SUPPRESSION of

antidiuretic hormone (ADH) [ ie. ADH should normally be suppressed- leading to less water retention and a more dilute urine ]

= SIADH
2. Inability to maximally dilute the urine
= Diuretics

Front 22

A urine sodium < 20mmol/L indicates which

hyponatraemia category?

Back 22

HYPOvolaemic hyponatraemia

- GIT Losses [ vomiting / diarrhoea ]

Front 23

A urine sodium of > 20mmol/L indicates which category of hyponatraemia?

Back 23

EUVOlaemic Hyponatraemia.

Front 24

Which Causes of hyponatraemia would be

associated with a urinary sodium > 20mmol/L ?

Back 24

1. Euvolaemic hyponatraemia
- SIADH

2. Hypovolaemic hyponatraemia
- Diuretics
- adrenocortical insufficiency

Front 25

What 3 Endocrine diseases are associated with

hyponatraemia?

Back 25

1. Hypothyroidism
2. Hypopituitarism
3. Addison's Disease

Front 26

What are the main treatments for each group of hyponatraemia -

( Euvolaemic ; Hypovolaemic ; Hypervolaemic )?

Back 26

Euvolaemic:
1. Fluid restriction
2. +/- Withdraw causative drug
3. +/- Treat identifiable cause of SIADH
4. Hypertonic saline for severe < 120 mmol/L

Hypovolaemic
1. Volume expansion with Isotonic saline
2. treat underlying process

Hypervolaemic
1. Fluid restriction
2. Diuretics
3. Treat underlying process

Front 27

In regards to serum osmolarity, which of the

following levels and expected symptoms / signs is incorrect?
A. > 350 = excessive thirst
B. > 400 = ataxia / tremor
C. > 430 = hyperreflexia / focal Neurological deficit
D. > 430 = seizures / coma

Back 27

C : > 420 mOsm / kg = hyperreflexia / focal Neurological deficit

Front 28

In regards to serum osmolarity, which of the following levels is likely to be associated with seizures ?
A. > 350 mOsm/kg
B. > 400 mOsm / kg
C. > 430 mOsm/kg
D. > 450 mOsm/kg

Back 28

C. Seizures > 430 mOsm/kg

Front 29

In regards to serum osmolarity, which of the following levels is likely to be associated with ataxia?
A. > 430 mOsm/kg
B. > 400 mOsm/kg
C. > 350 mOsm/kg
D. > 320 mOsm/kg

Back 29

B. Ataxia > 400 mOsm/kg

Front 30

What is the normal measured serum

osmolarity ?

Back 30

Normal Serum osmolarity :

285 - 295 mOsm/kg

Front 31

What situations / patients are at an increased risk of developing Central Pontine Myelinosis with correction of hyponatraemia ?

Back 31

1. Hyponatraemia present for > 48 hours
2. Alcoholics
3. Malnourished
4. Elderly **

Front 32

What Clinical findings occur with

Central Pontine Myelinosis ?

Back 32

( aka : osmotic demyelination syndrome )

Progressively Develops over 3-5 days after

correction of the sodium :
1. Fluctuating conscious state
2. Seizures
3. Quadriparesis
4. Dysphagia + dysarthria
5. Mutism

Front 33

(2015)

List 4 indications for the use of 3% hypertonic saline in hyponatraemia.

Back 33

Na < 120 mmol/L

1. Seizures (active)

2. Delerium

3. Coma

4. Focal neurology

Front 34

( 2015)

List 3 important components to giving

hypertonic saline in hyponatraemia.

Back 34

3% saline -100mL- over 30-60 minutes.

"Rule of Threes" :

3mL/kg of 3% saline over 30 minutes raises [Na] by 4mmol.

Aim to increase the [Na] by no more than

0.5 mmol/Hr.

Front 35

(2015)

List 4 complications of administration of

hypertonic saline for symptomatic

hyponatraemia.

Back 35

1. Central Pontine myelinosis (CPM)

- flacced paralysis

- dysarthria / dysphagia

- hypotenion

2. Hypernatraemia

3. CCF / Pulmonary oedema

4. Rebound intracranial HTN.